Hello everyone,

a friend of mine recently purchased a modified 997.1tt that had a proto A28 setup, car ran well and was converted to A3076 then ran into some clutch problems ...

When the Gearbox came apart, we found the setup was As follows:

- Factory Lwfw: 964-102-239-31
- GT3RS 3.6 sprung disk: 996-116-015-32
- Sachs (751) Pressure plate

The damage was in the needle bearings, but the clutch showed signs of advanced wear and we knew the 751 plate was inadequate for the power to be had. So we decided to change the pressure plate and clutch disk, and convert to GT2 slave setup, so following parts were ordered and installed:

-Sachs (764) Pressure plate
-New Throwout bearing For LWFW: 944-116-080-01
-Sachs Clutch for 3.8RS/4.0RS/GT2RS - 997-116-013-91

I was assured (By those who supposedly know) that this setup will work and been tested again and again..

All parts go in, car taken out for brek-in/test and all we get is a horrible grinding noise, clutch feels like its both slipping and grinding metal parts, Something is not in order ... Down comes the gearbox and engine again, and we found (Please refer to pictures) that the Clutch disk center (Metal part) was grinding on the TO bearing, parts of the metal was grinded off.

Compared to the 3.6RS clutch, the 3.8/4.0RS Clutch has a different offset off the splined tube in the center, when laid side by side the 4.0Clutch is a good 1/2-3/4 inch higher ...

What is the catch? Can anyone who has done this conversion share the part numbers needed?

Do you need the 4.0/2RS Flywheel (964-102-239-81) For this conversion to work properly?

This car is going back to the old style clutch for now, but I'm interested as I'm doing this conversion to my car in the near future. The Clutch in the pictures is still brand new, is it totalled or the damage is just "Scratches" ???

Any help would be greatly appreciated,
Abdulla

 

You sure they didn't install the clutch disc backwards? The 4.0 disc goes in backwards compared to the old 996GT3RS disc. I run the 764PP/4.0disc/964RS LWFW combo. No issues... You can also use the 4.0RS LWFW, it's 1.5lbs lighter than the 964 RS. It's the same part with more material milled out of it. This is what you need for the conversion:

Sachs 764 clutch pressure plate (88.3082.999.764)
997GT3RS 4.0 clutch disc (997.116.013.91)
964 LWFW (964.102.239.31)
Flywheel bolts 9x (928.102.151.01)
Pilot bearing (931.102.111.00)
Throwout bearing (944.116.080.01)
Guide tube (950.116.813.30)
Guide tube bolts 2x (999,270.070.01)
Ring gear (964.114.143.31)
Pressure plate bolts 9x(999.510.015.02)

 

Hi and thanks for the reply,

Your parts list is the same as our car, but this combo didn't work

What do you mean installed backwards? The tech installed it as labeled on the Clutch disk (Gearbox Side) facing the TO bearing/ Pressure plate. Is the Clutch plate labelled wrong? Do we install the gearbox side facing the engine/Flywheel? If so, When using the updated Flywheel (964.102.239.81) does the clutch need to be installed backwards too?

Sorry I have so many questions but this is straining my brain. Why would they label it wrong. (Aren't they German? )


I found a picture from another forum showing the difference in the flywheel design ....

 

http://rennlist.com/forums/997-gt2-g...mber-help.html

Post #8: Confirms what pwdrhound mentioned .... Thanks you for the info mate ....

 

Anyone can provide some assistance here please?

I informed the tech about the backwards install, he tried and says the clutch disk hub is too big for the flywheel and it still rubs?

To those who have done this(LWFW + 4.0disk), could you please confirm which Flywheel is on your car.

Many thanks

 

Sorry for your troubles. As I suspected they installed it backwards. I'd get another competent tech. This combo has been done countless times including one guy that runs the exact same set up on his 997TT in my area with the parts I listed earlier. It will work with both the 996Cup and 964RS flywheel (964.102.239.31).

 

Thank you for confirming ...

 

Interesting, isn't the gt2rs fw the same pn as the 4.0rs?

 

yes, (964.102.239.81) ... Put an order last night for the complete 2RS/4.0 setup including this flywheel, will update this thread when everything is here ..